How Does Motorcycle Traction Control Work?


How Does Motorcycle Traction Control Work?
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Traction control has been part of the automotive world for years now. For motorcycles, however, traction control systems are still in their infancy. Even so, they’ve come a good distance in a very short period of time and are now standard fare on many different models of motorcycles. We’re going to give you a basic look at motorcycle traction control systems in order to make them seem less like black magic and more like the technological marvels they are.

There are two types of traction control: reactive and predictive. Simply put, reactive systems wait until wheel spin occurs, and then make a correction. Predictive systems constantly read information and make a correction just before wheel spin occurs. There are a few different tools that motorcycle traction control systems use to achieve this.

  • Gyroscopes – Measure lean angle.
  • Wheel speed sensors – Detect sudden changes in wheel speed while taking speed readings multiple times per second.
  • Accelerometers – Monitor acceleration.
  • Throttle position sensor – Measure how far open the throttle is.
  • Gear position sensor – Monitors what gear you are in.
  • Engine speed sensor – Monitors rpm.

Different manufacturers use different combinations of the above tools. Since throttle position sensors, gear position sensors and engine speed sensors are pretty much standard on most of today’s motorcycles, the ECU collects that information and puts it together with the information it gets via other means. Sometimes, a manufacturer spares no effort in programming the information a motorcycle’s ECU is capable of collecting. A fine example of a modern traction control system is the six-axis IMU that Yamaha uses on its 2015 YZF-R1. This unit measures pitch, roll, yaw, and gravitational forces in each direction, making it sound very much like an aviation instrument. This just goes to show the strides manufacturers are still making in TC.

Once they’ve collected their information, all these gizmos then have go about throwing out the safety net. In general, this means that the computer must take power away in the event of a wheel spin. There are different ways in which that is done:

  • Ignition retard – This directly affects power delivery by softening the power the engine makes. It makes for a fine adjustment, but has the most limited effect because excessive retardation basically causes a cylinder misfire. Thus, it is generally used in conjunction with at least one of the following methods.
  • Cylinder misfiring – In this case, the ECU will simply cut the fuel supply to a particular cylinder (instead of using excessive ignition retard). It is not a fine method of adjustment, but it very effectively limits power. You can actually hear this system work. When you apply power while leaned over, the exhaust note will go from smooth to raspy until you come out of the lean. If you watch World Superbike racing, this is especially evident with the Kawasaki ZX-10R (which sounds pretty cool).
  • Electronic throttle adjustment – Think of this as a ghost right wrist that basically limits the power that the throttle can dole out. You could, in a crude sense, hold the throttle wide open and only a certain amount of power could ever be applied. This system is used on motorcycles that feature wide-by-wire throttle as opposed to the traditional cable-controlled throttle. It’s a classic case of digital versus analog.

Again, these methods are used in different combinations depending on the manufacturer. A system that uses all three methods has the potential to offer the most comprehensive level of traction control. A tantalizing prospect. Some bikes have built-in presets that you can choose from, while others offer very fine levels of adjustment. If you prefer, you sometimes have the option of turning all this gadgetry off, but you’d better be sure you have the skill to handle what’s coming.

It’s easy to think of traction control (or any rider aid, for that matter) as a crutch you can lean on rather than your own abilities. Despite the technological advances, remember that it is important that you refine your own skills. Traction control is merely here to help you as you hone your skills, and hopefully, we’ve given you enough information to set you on your way to understanding motorcycle traction control.

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